U.S. patent number 5,014,593 [Application Number 07/423,657] was granted by the patent office on 1991-05-14 for perforated plate armor.
This patent grant is currently assigned to General Dynamics Land Systems, Inc.. Invention is credited to Richard A. Auyer, Robert J. Buccellato, Andrew J. Gidynski, Richard M. Ingersoll, Needangalam S. Sridharan.
United States Patent |
5,014,593 |
Auyer , et al. |
May 14, 1991 |
Perforated plate armor
Abstract
Perforated plate armor (10) for protecting an object (12) from
damage includes outer and inner perforated steel plates (14) and
(18) which have associated patterns of holes (16,20). These
perforated steel plates (14,18) are heat treated to have hardened
surfaces and a more ductile core and are spaced with respect to
each other at outer and inner locations with respect to the object
(12) to be protected. The patterns of holes (16,20) of the
perforated steel plates (14,18) are offset with respect to each
other to prevent straight line penetration of any particle through
both plates. An inner backing plate (28) preferably made of
aluminum is also provided to stop any particles that might
penetrate both perforated steel plates (14,18). Fillers (22,24) and
connectors (26) space the outer and inner perforated steel plates
(14,18) and the aluminum backing plate (28) with respect to each
other.
Inventors: |
Auyer; Richard A. (Troy,
MI), Buccellato; Robert J. (Livonia, MI), Gidynski;
Andrew J. (Sterling Heights, MI), Ingersoll; Richard M.
(Troy, MI), Sridharan; Needangalam S. (Ortonville, MI) |
Assignee: |
General Dynamics Land Systems,
Inc. (Troy, MI)
|
Family
ID: |
26858861 |
Appl.
No.: |
07/423,657 |
Filed: |
October 18, 1989 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
162555 |
Mar 1, 1988 |
|
|
|
|
Current U.S.
Class: |
89/36.02;
109/84 |
Current CPC
Class: |
F41H
5/0457 (20130101) |
Current International
Class: |
F41H
5/00 (20060101); F41H 5/04 (20060101); F41H
005/013 (); F41H 005/04 () |
Field of
Search: |
;89/36.02,36.01,36.04,36.08,36.12 ;428/911,71,73 ;109/79,82,84
;52/309.9,309.11 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
36056 |
|
Aug 1908 |
|
AT |
|
2201637 |
|
Aug 1973 |
|
DE |
|
3506004 |
|
Aug 1986 |
|
DE |
|
866796 |
|
Sep 1941 |
|
FR |
|
909792 |
|
May 1946 |
|
FR |
|
1102646 |
|
Oct 1955 |
|
FR |
|
1566448 |
|
May 1969 |
|
FR |
|
2447272 |
|
Aug 1980 |
|
FR |
|
306191 |
|
Dec 1939 |
|
IT |
|
8404156 |
|
Oct 1984 |
|
WO |
|
543645 |
|
Mar 1942 |
|
GB |
|
2107608 |
|
May 1983 |
|
GB |
|
Primary Examiner: Jordan; Charles T.
Assistant Examiner: Johnson; Stephen
Attorney, Agent or Firm: Brooks & Kushman
Parent Case Text
This is a continuation of copending application Ser. No. 07/162,555
filed on Mar. 1, 1988, now abandoned.
Claims
What is claimed is:
1. Perforated plate armor comprising: an outer perforated steel
plate having a pattern of spaced triangular holes an inner
perforated steel plate having a pattern of spaced triangular holes;
each of said outer and inner perforated steel plates having
oppositely facing surfaces and having hole defining surfaces; the
hole defining surfaces of each of said inner and outer steel plates
extending between the oppositely facing surfaces of the associated
plate about the entire periphery of each triangular hole therein;
each of said outer and inner perforated steel plates being heat
treated to have hardened surfaces and a more ductile core; an inner
backing plate; each of said outer and inner perforated steel plates
and said inner backing plate having mounting holes; connectors each
of which includes a connector member that extends through a pair of
said mounting holes in the outer and inner perforated steel plates
and through one of said mounting holes in the inner backing plate;
each of said connectors including spacers that are separate from
each other and said spacers having openings through which the
connector member thereof extends with at least one spacer of said
spacers located between the outer and inner perforated steel plates
and with at least one spacer of said spacers located between the
inner perforated steel plate and inner backing plate; the connector
member of each connector having a pair of ends where the connector
member respectively extends through one mounting hole of said
mounting holes of the outer perforated steel plate and through one
mounting hole of said mounting holes of the inner backing plate to
provide engagement of the outer and inner perforated steel plates
and the inner backing plate with the spacers; and the connectors
locating the outer and inner steel plates with the pattern of
spaced triangular holes of the outer steel plate in an offset
relationship to the pattern of spaced triangular holes of the inner
steel plate to limit projectile penetration.
2. Perforated plate armor as in claim 1 wherein the inner backing
plate is made of aluminum.
3. Perforated plate armor as in claim 2 further including a filler
located between the inner perforated steel plate and the aluminum
backing plate.
4. Perforated plate armor as in claim 3 wherein the filler is
selected from a group consisting of foam, plastic, and wood.
5. Perforated plate armor as in claim 4 further including a filer
located between the outer and inner perforated steel plates.
6. Perforated plate armor as in claim 5 wherein the filler between
the outer and inner perforated steel plates is selected from a
group consisting of foam, plastic, and wood.
7. Perforated plate armor as in claim 1 further including an
integument in which the inner and outer perforated steel plates and
the inner backing plate are enclosed.
8. Perforated plate armor as in claim 7 wherein in the integument
includes a fiberglass mat.
9. Perforated plate armor as in claim 8 wherein in the integument
also includes a veil cloth covering the fiberglass mat.
Description
TECHNICAL FIELD
This invention relates to steel armor plate for protecting objects
such as vehicles from incoming objects or from other types of
attack that can cause damage.
BACKGROUND ART
Armor plate of hardened steel has been used for many years to
provide protection of objects against damage. Vehicles such as
tanks, military sites, vaults, and safes, etc. have used steel
armor plate to provide such protection.
In order to increase the protection provided, it has previously
been proposed to use spaced layers of steel. For example, U.S. Pat.
No. 1,548,441 Branovich discloses an armor protected fuel tank
wherein a layer of wood and a layer of semi-cured rubber are
positioned between a steel tank and an outer armor plate. U.S. Pat.
No. 2,348,130 of Hardy, Jr. discloses spaced metal plates between
which a layer of rubber is positioned with pockets in the rubber
filled with abrasive material such as sand. U.S. Pat. No. 2,733,177
Meyer discloses an elastic cascading impact absorber wherein layers
of armor are spaced with respect to each other by elastic material
which is disclosed in preferred embodiment as being formed sheet
metal springs. U.S. Pat. No. 4,455,801 Merritt discloses a
lightweight vault wall wherein layers of metal, stainless steel and
aluminum, cover spaced layers of plywood adjacent each of which is
provided a layer of expanded metal mesh that is spaced from the
other layer of expanded metal mesh by a foamed plastic core.
Two different basic types of armor plate are conventionally
utilized at the present time. One type is high-hard armor that is
extremely hard and thus capable of preventing penetration of
penetrating type of projectiles. The other type is rolled
homogenous armor that is somewhat softer than high-hard armor but
is more ductile so as to prevent brittle fracture. Prior art
references which disclose compositions and processing used in
hardening of steel plates include: U.S. Pat. Nos. 774,959
Tresidder; 1,043,416 Giolitti; 1,079,323 Benthall; 1,097,573 Wales;
1,563,420 Johnson et al; and 1,995,484 Sullivan as well as the
previously mentioned U.S. Pat. No. 2,733,177 Meyer.
In order to decrease weight, armor plate and the like have
previously included holes such as illustrated by U.S. Pat. No.
3,763,838 of Butterweck et al which discloses a protective
shielding for vehicles. While circular holes such as disclosed by
Butterweck et al or slots are the easiest to produce in armor by
punching, such shapes have ballistic gaps that reduce the
protection provided. Similarly, square holes which will provide the
lowest weight also have ballistic gaps that reduce the protection
provided.
Other prior art references disclosing armor plate or the like
include U.S. Pat. Nos.: 45,536 Terwilliger et al; 874,729 DeBolula;
and 4,178,859 Seiz et al.
DISCLOSURE OF INVENTION
An object of the present invention is to provide perforated plate
armor for protecting an object from damage by incoming
projectiles.
In carrying out the above and other objects, perforated plate armor
constructed in accordance with the present invention includes outer
and inner perforated steel plates each of which has an associated
pattern of spaced holes. Each of the steel plates is heat treated
to have hardened surfaces and a more ductile core, and the steel
plates are supported in a spaced relationship to each other at
outer and inner locations with respect to an object to be
protected. The hole patterns of the outer and inner perforated
steel plates are offset with respect to each other so as to prevent
straight line penetration of a projectile particle of any
significant size through both plates.
In the preferred construction, the perforated plate armor also
includes an inner backing plate for stopping any particles that
pass through both perforated plates. This inner backing plate is
preferably made from aluminum when taking into consideration both
strength and weight factors.
A first filler is located between the spaced outer and inner
perforated steel plates, and a second filler is located between the
inner perforated steel plate and the aluminum backing plate. These
fillers are made from any suitable lightweight material such as
foam, plastic, or a lightweight wood like balsa wood.
Spacers separate the outer and inner perforated steel plates from
each other and also space the inner perforated steel plate from the
aluminum backing plate. These spacers are thus located in alignment
with the fillers with a corresponding thickness for providing the
plate spacing. Best results are achieved when the aluminum backing
plate is spaced inwardly from the inner perforated steel plate a
greater distance than the spacing between the outer and inner
perforated steel plates, most preferably about five to seven times
the spacing between the outer and inner plates.
Connectors are also provided for securing the outer and inner
perforated steel plates to each other and to the backing plate with
the spacers located between the plates. These connectors preferably
extend through the spacers which have annular shapes such that the
spacers extend between the outer and inner perforated steel plates
and the aluminum backing plate to cooperate in the securement of
all of the plates to each other in a spaced relationship.
As disclosed, the perforated plate armor also includes an
integument in which the outer and inner perforated steel plates are
enclosed. This integument preferably includes a fiberglass mat and
a veil cloth covering the fiberglass mat.
The objects, features, and advantages of the present invention are
readily apparent from the following detailed description of the
best mode for carrying out the invention when taken in connection
with the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a perspective view that is partially broken away in
section to illustrate an armor plate module including perforated
armor plate embodying the present invention;
FIG. 2 is a plan view that illustrates the hole pattern of an outer
steel plate of the armor plate module;
FIG. 3 is a plan view that illustrates the hole pattern of an inner
steel plate of the armor plate module;
FIG. 4 is a plan view that illustrates an offset relationship of
the hole patterns of the outer and inner steel plates of the armor
plate module when mounted with respect to each other as illustrated
in FIG. 1;
FIG. 5 is a sectional view taken along the direction of line 5--5
in FIG. 1 to illustrate the construction of connectors that connect
the outer and inner steel plates to each other in a spaced
relationship; and
FIG. 6 is a schematic view that illustrates processing used to
provide the steel plates of the armor plate module.
BEST MODE FOR CARRYING OUT THE INVENTION
With reference to FIG. 1 of the drawings, an armor plate module
generally indicated by 10 embodies the present invention as is
hereinafter more fully described and provides protection for an
object 12 such as the outer skin of a vehicle. The armor plate
module 10 includes an assembly of perforated plate armor having an
outer perforated steel plate 14 with a pattern of spaced holes 16.
Armor plate module 10 also includes an inner perforated steel plate
18 having a pattern of spaced holes 20. As is hereinafter more
fully described, each of the outer and inner steel plates 14 and 18
is heat treated to have hardened surfaces and a more ductile core.
A pair of fillers 22 and 24 and connectors 26 provide a means for
supporting the outer and inner perforated steel plates 14 and 18 in
a spaced relationship to each other at outer and inner locations
with respect to the object 12 to be protected. In this assembled
condition, the pattern of holes 16 of the outer steel plate 14 and
the pattern of holes 20 of the inner steel plate 18 are offset with
respect to each other as illustrated in FIG. 4 to thereby cooperate
in preventing a projectile from penetrating straight through both
plates. Each of the outer and inner perforated steel plates 14 and
18 has oppositely facing surfaces as best shown in FIG. 5. The
spaced holes 16 and 20 of the plates 14 and 18 each have a hole
surface that extends between the oppositely facing surfaces of the
plate about the entire periphery of the hole. This construction
results in less material than an imperforate plate so as to thereby
provide lightweight protection.
As shown in both FIGS. 1 and 5, the perforated plate armor provided
by the module 10 also includes an inner backing plate 28 for
stopping any particles that might pass through both perforated
steel plates 14 and 18. This inner backing plate 28 is most
preferably made from aluminum when taking into consideration both
weight and strength factors.
The one filler 22 is located between the outer and inner perforated
steel plates 14 and 18 to fill the spacing between these two
plates, while the other filler 24 is located between the inner
perforated steel plate 18 and the aluminum backing plate 28 to
likewise fill the spacing between these two plates. Both of the
fillers 22 and 24 can be made from any suitable material that is
lightweight while still having the requisite strength such as foam,
plastic, or a lightweight wood like balsa wood.
With combined reference to FIGS. 1 and 5, the connectors 26 include
spacers 30 that space the outer and inner perforated steel plates
14 and 18 with respect to each other. As illustrated, each
connector 26 includes a pair of the spacers 30 that space the outer
and inner steel plates 14 and 18 with respect to each other and
also includes a pair of spacers 30 that space the inner steel plate
18 with respect to the backing plate 28. It is also possible to
utilize a single spacer for separating each of the adjacent pairs
of plates; however, use of multiple spacers provides ease of
adjustment of the plate spacing by merely adding or removing one or
more spacers sized to provide best results. The spacers 30 have
annular shapes through which a bolt 32 of the associated connector
26 extends between the outer and inner perforated steel plates 14
and 18 and the aluminum backing plate 28. A head 34 of bolt 32 is
engaged with the backing plate 28 as illustrated, while a nut 36
threaded onto the bolt 32 holds the outer steel plate 14 as shown
in FIG. 5.
With reference to FIG. 1, the armor plate module 10 also includes
an integument 38 in which the outer and inner perforated steel
plates 14 and 18 are enclosed along with the first and second
fillers 22 and 24. This integument 38 preferably includes a
fiberglass mat covered by a veil cloth and functions to encase the
outer and inner perforated steel plates 14 and 18 and the first and
second fillers 22 and 24 as a module in association with the
connectors 26 that also secure the backing plate 28.
As illustrated in FIGS. 2 and 3, each of the hardened steel plates
14 and 18 has its associated holes 16 and 20 provided with
triangular shapes that are arranged in a repeating pattern.
Specifically, the triangular holes 16 of the outer perforated steel
plate 14 shown in FIG. 2 are arranged in rows 16a and columns 16b.
Webs 40 of the plate 14 separate the triangular holes 16 along each
row 16a, while webs 42 separate the triangular holes 16 along each
column 16b. Likewise, the inner steel plate 18 shown in FIG. 3 has
its triangular holes 20 arranged in rows 20a and columns 20b in the
same manner with webs 44 spacing the triangular holes 20 along each
column 20a and with webs 46 spacing the triangular holes 20 along
each column 20b. This construction of each steel plate 14 and 18
provides lightweight armor plate without ballistic gaps that would
occur with other shapes such as round or slotted holes that are
easier to form by a punching operation or with square holes that
provide the most lightweight construction possible.
As shown in both FIGS. 2 and 3, the triangular holes 16 and 20 of
each of the steel plates 14 and 18 are shaped and positioned with
respect to each other such that the associated webs 40,42 and 44,46
are generally straight. The triangular holes 16 and 20 of each
steel plate preferably have the same size and shape as each other
and are most preferably constructed as equilateral triangles.
Adjacent triangular holes 16 and 20 with the equilateral shapes
along the rows 16a and 20a are rotated at 120.degree. with respect
to each other to provide the generally straight webs 40 and 44
between the adjacent triangular holes. Along the columns 16b and
20b of each steel plate, the associated triangular holes 16 and 20
have the equilateral shapes thereof provided with the same
orientation and are separated from the adjacent triangular holes in
the column by the generally straight webs 42 and 46.
Referring to FIG. 2, the outer steel plate 14 is provided with
round mounting holes 48 that are positioned generally along the
webs 42 that separate one of the rows 16a of triangular holes 16
from an adjacent row 16a. Each round mounting hole 48 is located in
alignment with the triangular holes of one column 16b as well as
being in alignment with the webs 42 that separate adjacent rows
16a.
As illustrated in FIG. 3, the inner steel plate 18 has round
mounting holes 50 aligned along associated rows 20a of the
triangular holes 20. These round mounting holes 50 are also aligned
along associated columns 20b.
As shown in FIG. 5, the bolt 32 of each connector 26 extends
through the round mounting holes 48 and 50 of the outer and inner
perforated steel plates 14 and 18 as well as through a bushing 52
in a round mounting hole 54 of the aluminum backing plate 28 to
provide the assembly as previously described. The offset hole
relationship shown in FIG. 4 is provided by the combination of the
location of the round mounting holes 48 of the outer plate 14 as
shown in FIG. 2 in alignment with the webs 42 between the adjacent
rows 16a, the location of the mounting holes 50 of the inner steel
plate 18 in alignment with the rows 20a, and rotation of the outer
steel plate 14 180.degree. from the position shown in FIG. 2 with
respect to the inner steel plate 18 shown in FIG. 3. This offset
relationship of the hole patterns prevents straight line
penetration of any projectile of any significant size through both
steel plates.
In one preferred embodiment of the armor plate module 10, the outer
steel plate 14 has a thickness of about 3/8 of an inch and the
inner steel plate 18 has a thickness of about 1/4 of an inch while
the first filler 22 has a thickness of about 1 inch and the second
filler 24 has a thickness of about 5 to 7 inches. Both the outer
and inner steel plates 14 and 18 have their equilateral triangular
holes provided with the same size whose sides when extended at the
rounded vertices thereof have a length with the intersecting
adjacent sides of about 0.6495 inch such that the maximum circular
shape that can pass through each hole has a diameter of 3/8 of an
inch. The center of the holes are uniformly spaced along the rows
16a and 20a by a distance of 0.5540 of an inch, while the centers
of the holes are uniformly spaced along the columns 16b and 20b by
a distance of 0.6945 of an inch. The webs 40 and 44 between the
triangular holes along each row 16a (FIG. 2) and 20a (FIG. 3) have
a width of about 0.1985 inches. Between the adjacent rows 16a shown
in FIG. 2 and and the adjacent rows 20a shown in FIG. 3, the sides
of the triangular holes 16 and 20 are spaced from each other by
about 0.1320 of an inch with a somewhat greater spacing being
provided between each side and the adjacent hole apex due to its
rounding. The mounting holes 48 and 50 of each steel plate are
spaced from each other by seven rows from each other such that
their centers are spaced by about 4.8615 inches along the length of
each column. Furthermore, the mounting holes 48 and 50 are spaced
from each other by ten columns such that their centers are located
about 5.54 inches from each other along each row.
As is hereinafter more fully described, each of the steel plates 14
and 18 previously described is heat treated to provide carbonitride
surfaces and a tough, ductile core. The carbonitride surfaces have
a hardness of at least 66 on the Rockwell C scale to prevent
surface penetration, while the tough, ductile core which is softer
than the carbonitride surfaces prevents brittle fracture of the
steel plate. More preferably, the carbonitride surfaces have a
surface hardness of at least 67 on the Rockwell C scale to provide
greater resistance to penetration.
It is possible to manufacture the plate armor from steel plates of
the rolled homogenous type. With rolled homogenous armor, the core
hardness is in the range of about 45 to 50 on the Rockwell C scale.
Many types of rolled homogenous armor are available for use and
have the general composition shown by the following Table I.
TABLE I ______________________________________ Maximum Maximum
range limit Element percent percent
______________________________________ Carbon 0.10 0.28 Manganese:
Up to 1.00% incl. 0.30 -- Over 1.00% 0.40 -- Phosphorus -- 0.025
Sulfur -- 0.025 Silicon: Up to 0.60% incl. 0.20 -- Over 0.60% to
1.00% incl. 0.30 -- Over 1.00% 0.40 -- Nickel 0.50 -- Chromium: Up
to 1.25% incl. 0.30 -- Over 1.25% 0.40 -- Molybdenum: Up to 0.20%
incl. 0.07 -- Over 0.20% 0.15 -- Vanadium: 0.15 --
______________________________________
It is also possible to manufacture the plate armor from steel plate
that is made from high-hard armor. With high-hard armor, the steel
plate will have a core hardness in the range of about 52 to 54 on
the Rockwell C scale. High-hard armor is also commercially
available with the general composition as shown by the following
Table II.
TABLE II ______________________________________ Maximum Maximum
range limit Element percent percent
______________________________________ Carbon 0.10 0.32 0
Manganese: Up to 1.00% incl. 0.30 -- Over 1.00% 0.40 -- Phosphorus
-- 0.025 Sulfur -- 0.025 Silicon: Up to 0.60 incl. 0.20 -- Over
0.60% to 0.30 -- 1.00% incl. Nickel 0.50 -- Chromium: Up to 1.25%
incl. 0.30 -- Over 1.25% 0.40 -- Molybdenum: Up to 0.20% incl. 0.07
-- Over 0.20% 0.15 -- Vanadium: 0.15 --
______________________________________
The thickness of steel plate utilized to provide the case hardened
plate armor is in the range of about 0.15 to 0.5 of an inch. Also,
the thickness of the carbonitride surfaces do not have to be
particularly deep, about 0.016 of an inch is sufficient to provide
the requisite surface hardness that is supported by the tougher,
more ductile core. While carbonitride surfaces have previously been
utilized to provide greater resistance to wear, such as on rotary
shaft wear surfaces, such hardening has never been previously
utilized to provide case-hardened plate armor in the manner herein
disclosed.
As disclosed, the plate armor has the holes formed therethrough
prior to the heat treating. As previously mentioned, it is
preferable for the holes to have the same size and shape as each
other arranged in the type of repeating pattern previously
described. Also, the webs between the holes preferably have a width
in the range of about 0.1 to 0.25 of an inch to provide best
results.
The process for performing the case hardening of the steel plate
can be best understood by reference to FIG. 6. This process begins
by forming the holes prior to the heat treating. While it is
preferable to form the holes by a punching operation, it is also
possible to provide the holes by drilling, laser cutting, electron
beam cutting or any other type of process capable of accurately
providing holes through the steel plate.
After the formation of the holes, the steel plate is heated in an
atmosphere of nitrogen and carbon to provide the carbonitride
surfaces. Cracked ammonia and methane are preferably utilized to
readily provide the atmosphere of nitrogen and carbon. The heating
in this atmosphere is performed for about 1 to 3 hours at a
temperature in range of about 1300.degree. F. to 1550.degree. F.,
with the time being more critical than the temperature in
controlling the degree of hardening achieved.
After the initial heating, the steel plate is quenched to form
martensite. This quenching is preferably performed with oil to
prevent distortion and to also insure that all of the austenite is
changed to martensite.
After the quench, the steel plate is tempered to change the
martensite to tempered martensite and ferrite. This tempering of
the steel plate is preferably performed for 1/2 to 2 hours at a
temperature in the range of 275.degree. F. to 325.degree. F. in
order to effect the change of the martensite to the tempered
martensite and ferrite.
An air cool of the steel plate after the initial tempering precedes
a deep freeze step to permit cooling to the ambient without any
expenditure of energy. The deep freeze step is then performed to
change any retained austensite to martensite. This deep freezing is
preferably performed for 1 to 3 hours at a temperature in the range
of -50.degree. F. to -150.degree. F.
After the deep freeze step, the steel plate is again tempered to
change any additional martensite resulting from the deep freezing
to tempered martensite and ferrite. This additional tempering like
the initial tempering is preferably performed for 1/2 to 2 hours at
a temperature in the range of 275.degree. F. to 325.degree. F.
The carbonitride processing described above provides hard
carbonitride surfaces and a softer but more ductile core such that
the resultant steel plate is resistant to fracture as described
above.
While the best mode for carrying out the invention has been
described in detail, those familiar with the art to which this
invention relates will recognize various alternative designs and
embodiments for carrying out the invention as defined by the
following claims.
* * * * *